Why are UC Berkeley students not policing themselves?

With respect to the riots at UC Berkeley, if the student body president is correct and the rioters are not students, why did the students not stop them? Why did they allow them to hide in their crowd? Why did they not start grabbing rioters and turning them over to the police? By not doing so, they are in fact supporting those who believe they have the right to destroy other peoples property and commit acts of violence against them. And this invalidates everything they are supposed to stand for. Remember, your rights end where my rights begin. Perhaps we should all remember that. Shame on you, Berkeley students.